German police conducted on Friday a security operation at a shelter on Hamburg’s northern outskirts linked to the failed asylum seeker who stabbed a person to death, local media said.

Police officers in heavy riot gear searched a 590-bed asylum shelter Langenhorn where the knifeman had lived and had been radicalized, according to the Hamburger Morgenpost newspaper.

The attacker was identified as an asylum seeker named Ahmad A. who was born in the UAE. He stabbed a 50-year-old German man to death at an Edeka supermarket and injured six others.

Hamburg Mayor Olaf Scholz said the 26-year-old had been motivated by hate. He had been targeted for deportation but it had been put off as he lacked identity papers.

The Tagesspiegels newspaper reported that Ahmad had been known to German authorities as an Islamist. If confirmed, this would be another instance in a series of Islamist knife, ax and truck attacks in Germany that have left dozens of people dead or wounded since last year.